NEW DELHI: The Supreme Court on Friday nudged the CBI to register more corruption cases on the basis of the contentious Niira Radia tapes. NGO CPIL lawyer Prashan Bhushan said the tapes, which are being scrutinised by the CBI, include recorded telephone conversations about alleged corporate role in the appointment of former Director General of Hydrocarbons, VK Sibal.

Some of the tapes have not been made public yet, but the conversations were leaked in 2010 on the controversial allocation of airwaves to telecom companies. The court has directed a CBI probe into the issue.

"Cases must be registered by the CBI under the Prevention of Corruption Act. They are throwing light on something else, not only spectrum, but wider," Justice GS Singhvi said sitting on a two-judge bench.

Justice Singhvi also asked CBI to scrutinise the rest of the Radia transcripts within three months to check for any further criminality impinging on national security.

The court also asked the CBI to share the report with the income tax department. The court will pass some orders on whether to make the tapes public on next Tuesday. The rest of the issues will be dealt with on October 22.

Bhushan wants the court to order the government to make the tapes public, except the purely private conversations. He has alleged that the DGH, the key government figure in monitoring oil and gas contracts with companies, was appointed at the behest of a corporate house.

The DGH is appointed by the appointments committee of the Cabinet led by the prime minister. The appointment of the DGH has often been mired in controversy. The current DGH RN Choubey became the first IAS officer to head theDGH - the tech arm of the oil ministry.